Square wire and rectangular wire are normally used for windings such as those in motors and magnets. Roll forming of square and rectangular wire is well known. Examples of square and rectangular wire are shown in U.S. Pat. No. 3,417,593. While U.S. Pat. No. 3,417,593 claims a relatively light duty, hand held device for squaring small round wire, the general principle of rolling stock between perpendicular sets of parallel flat rolls is similar to the method of rolling square or rectangular wire in a rolling mill. Aside from the obvious differences required for more heavy duty rolling mills such as drive trains and strain resistant components, a major difference is that the work rolls normally have predetermined grooves which cooperate to substantially enclose the stock on all sides in order to prevent undesired deformation of the stock in directions parallel to the axis of the work rolls by affirmative control. An example of such work rolls is disclosed in U.S. Pat. No. 4,193,823. Rolls for forming square or rectangular wire must have rectangular grooves. Such rolls are shown at FIG. 2 of U.S. Pat. No. 3,848,447. The typical rolling stand of a rectangular wire rolling mill is of the straddle mount type shown in U.S. Pat. Nos. 3,848,447 and 3,691,809 which require extensive dismantling of the mill in order to change rolls when roll pass dimensions need to be changed.